Gliederung

Introduction: For cell and tissue transplantation, novel concepts to facilitate engraftment are needed. To ensure the survival of a maximum of transplanted cells, rapid vascularisation is crucial. We used an arterio-venous chamber model to construct a perfect vascularised bed for tissue transplantation. In a first step we investigated optimal vascularisation conditions at different times.

Materials and methods: A vascularised chamber was implanted in the groin of 9 Lewis rats (9 weeks old). Forming an AV-loop with a venous interponat using 10*0 nylon sutures, the femoral artery and vein were inserted into a polycarbonat chamber and covered with 300μl Matrigel Growth Factor reduced, 1 μg/ml bFGF-2 and 80 U/ml Heparin. The explantation of the chamber was accomplished on day 3, 6, 9, 12, 15, 18, 21, 24 and 27. The explants were explored by stereomicroscopy, hematoxylin-eosin staining and immunocytochemistry.

Results: At time of chamber explantation there was no evidence of loop occlusion in any animal. In the first 10 days only few proliferation from the loop into the Matrigel was observed. Using hematoxylin-eosin staining, the distance of the tissue growth from the loop into the matrix was calculated. The main increase in proliferation was noted on day 15 with a range of 210μm away from the loop. Immunocytochemistry showed colocalisation of the grown loop tissue and newly formed vascularisation by CD31. The highest progress of proliferation was demonstrated from day 15 to 18 with a formation of 2751 new cells per field of view.

Conclusion: As a new matrix for tissue transplantation, Matrigel Growth Factor reduced with bFGF-2 and Heparin can induce proliferation and angiogenesis from an arterio-venous system inserted in a polycarbonat chamber. According to our results, the best time-point to transplant tissue into the chamber will be on day 15 in the inner part of the loop.